2011 巻 (2011) 56 号 p. 43-47
The committee members conducted the research of spring elastic limit for spring materials. Those testing instruments used in this research were APT type tester, Siemens tester and a newly developed prototype tester. The first two traditional testers are the possessions of member companies. The measurement by APT type and Siemens tester were in good correlation. The prototype tester displayed almost equal level reading with Siemens tester as far as the spring elastic limit is concerned. Modulus of elasticity reading by the prototype tester, however, were 10∼20 GPa higher than Siemens tester reading. The newly developed prototype tester has capability for the display of load-deflection diagram of thin specimen down to 0.05mm as well as measuring spring elastic limit.